Fan



$1M 31,1936. H. c. HUEGLIN FAN Filed May 9, 1935 Patented Mar. 31, 1936 UNITED STATES PATENT OFFICE FAN Herman C. Hueglin, Chicago,

111., assignor to Federal Merchandise Company, Chicago, 111.,

a corporation of Illinois Application May 9, 1935, Serial No. 20,520

g 4 Claims. (Cl. 230261) v ventilators, nor to operation on air, but may be employed elsewhere as suitable or desired.

Where the fan is used in a ventilator, the ventilator may comprise a-fan and a driving motor provided with a bracket for mounting the fan and motor in a panel, which panel may, in turn, be adapted for mounting in or over a window or other opening, or the fan may be used in connection with a stand for pedestal such as that shown in my copending application, Serial No. 17,562, filed April 22, 1935, or otherwise as suitable or desired.

The present invention has for one of its objectsv the provision of a fan having means for preventing the fan from drawing air in centrally from the discharge side.

Another object is to form pockets for the air which is thrown off the blades by the centrifugal motion, the tips of the blades beyond the pockets throwing the air forward and, with the present improvement, providing a much greater velocity of. air at the outside margins of the pockets.

Another and more specific object is to form the pockets above referred to and prevent the fan from drawing air in centrally from the discharge side by the simple expedient of a disc centrally disposed and secured in place to the discharge side of the fan, and, still more specifically, by means of a disc centrally disposed and secured in place to the discharge side of a fan having blades with inner. scooped or bucket-shaped portions behind the disc and outer blade portions extending outwardly from the periphery of the disc and adapted for throwing the air forward.

.Furtheroobjects and the advantages and details of the illustrated embodiment of the invention will appear from the following detailed description, taken in connection with the accompanying drawing, in which:

Figure 1 is a perspective view of a fan embodying the present invention;

' Figure 2 is an elevational view of the discharge side of the fan, with the centrally disposed disc secured thereto partially broken away to reveal the means on one of the blades for attachment of the disc thereto; and

Figure 3 is a more or less diagrammatic longitudinal section showing how the fan is prevented from drawing air in centrally from the discharge side and how the air is pocketed centrally, moved outwardly, and then forward by the blade portions beyond the periphery of the disc.

Referring to the drawing, the fan selected for illustration comprises a collar or hub portion 10 which is substantially cylindrical in form and which is bored centrally thereof, as shown in Figure 1, to form a cylindrical bearing portion l l adapted to receive a rotating shaft or the like to which the fan is secured.

10 A set screw I2 is threaded into the collar l0 radially thereof and is provided with a polygonal recessed head opening for insertion of a suitable tool to thread the set screw with respect to the shaft to secure the fan firmly to the shaft for rotation therewith. Integral with the forward end of the hub I0 is the hub or central portion M of the fan proper, which hub portion M has the integral fan blades l5 extending radially outwardly therefrom. The fan shown has five blades, but it is to be understood that the number of blades may be varied within the scope of the present invention.

The structure of the fan proper is similar to the structure of the fan shown in my copending application, Serial No. 704,826, filed January 2, 1934. The blades l5 are integrally connected to the hub portion It by means of the relatively small angularly extending tapered portions I6 of the blades, which produces a hub of relatively small area and also reduces the quantity of metal required. Substantially the entire outer portion I! of each blade l5 from the tip E8 to the section indicated at I9 is of the same curvature and pitch. These outer blade portions I! may be of relatively slight forwardly directed concave formation from one radial edge of each blade 15 to the other edge of the blade, or the concavity may be decreased to such an extent as to provide 7 substantially planar surfaces if desired. In the illustrated embodiment of the invention, all sections of each blade l5 between the tip l8 and the section 19 are substantially identical, and the outer portion of each blade is thus rendered uniform in pitch and curvature throughout its entire length.

The remainder or inner portion 20 of each blade l5, between the section l9 and the tapered connecting portion i6, is of scooped or bucketshaped formation. From the section blade is hollowed out inwardly and reaches its greatest concavity at the section 2| approximately midway between the section I9 and the outer end of the tapered connecting portion 16 between the blade and the hub of the fan. The pitch I9, the

the section I9 to the section I6, the blade is hol.

lowed out to give it a great concavity and, at the same time, is slightly warped to increase the pitch thereof. At the section I6, connecting the blade to the hub, the pitch angle has increased to approximately 75, whereas the pitch angleof the outer portion ll of the blade is approximately only 35 and remains at this angle from the outer tip I8 until the section I9 is reached. Fromthis point or section I9, there is a progressive increase in pitch, with a maximum concavity at the section 2I, and a decreasing concavity from there to the section I6.

At the point I5, where the blade joins the hub, the blade is of relatively small lateral extent. However, the metal is preferably thickened at this point to provide the necessary support and rigidity for the blade, but the surface adjacent the hub has been, to a large extent, eliminated by increasing the pitch angle and decreasing the lateral extent of the blade at the same time, there being a sharp taper from the section 20 to the section I6, as shown. The blade I has its greatest lateral extent adjacent the section 2I, which is the bottom or concave portion of the bucket-shaped inner portion of the blade.

A thin sheet-metal disc 25 of a diameter to cover the outer sides of the inner concave or bucketshaped portions of the blades I5 is disposed centrally of the fan and secured in place to the forward or discharge side of the fan, as by means of screws 26, or in any other suitable or preferred manner. In the illustrated embodiment of the invention, the forward or leading edge of each blade is thickened slightly or provided with a boss, as shown at 21, adjacent the outer end of the scooped portion 20, and these thickened portions or bosses 21 have tapped openings 28 into which screws 26 are threaded to secure the disc in centered position on the discharge side of the fan. The blades I5 are preferably undercut, as shown at 29 (Figures 2 and 3), so that the disc 25 lies flush with the forward or leading edges of the blades I5 at the discharge side of the fan.

The outer periphery of the disc 25 lies substantially along the sections I9 where the inner ends of the outer blade portions I! of constant pitch and curvature meet the outer ends of the inner scooped or bucket-shaped blade portions 2I. With this disc 25 thus arranged, the fan is prevented from drawing air in centrally from the discharge side. And, at the same time, pockets 30 are formed behind the disc 25, there being one of such pockets 30 between the disc 25 and each inner scooped or bucket-shaped blade portion 2|.

Thesepockets 30 catch or scoop up the air or other fluid which is thrown outwardly of the inner scooped or bucket-shaped portions ZI and to the 70 outer blade portions I! by the centrifugal motion. The outer blade portions I! extend beyond the disc 25 and throw the air or other fluid forwardly. The present improvement provides a much greater velocity of the air at the outside edge of the disc 25, in addition to preventing the fan from drawing air in centrally from the discharge side thereof. And this is all accomplished by the simple expedient of the disc 25 centrally disposed and secured in place to the discharge side of the fan and, in its more specific aspects, by the combination of this disc with the blade structure illustrated and described. The disc 25 is also adapted for closing the opening through the hub I4 on the discharge side of the fan, so that this opening may extend entirely through the hub I4 without exposing the same at the discharge side fan.

The thickness of each blade I5 may be progressively increased from the outer tip I8 to the point I6 where the blade is joined to the hub, as dis closed in my last mentioned copending application. As explained therein, this serves to provide the proper proportioning of the blade and disposes the center of gravity at the hub, reducing the inertia and producing less centrifugal force.

Each blade I5 may be provided on its back side and substantially centrally between its leading and trailing edges with a thickened strengthening rib extending from the tip of the blade to the section I6 which connects the blade to the hub of the fan. These ribs 35 conform to the formation of the backs of the blades and impart the desired strength and rigidity to the blades which, otherwise, may be relatively thin.

I do not intend to be limited to the precise details shown or described, except as set forth in the appended claims.

I claim:

1. A fan comprising a hub, a plurality of blades...

extending from said hub, each of said blades hav ing an outer portion of substantially constant pitch and curvature and an inner generally scooped portion, and means secured to the fan adjacent one side of said inner scooped portions of the blades and covering only the inner scooped portions of said blades at the discharge side of the fan and of a radial extent to leave the outer blade portions of constant pitch and curvature open at the discharge side of the fan, said inner scooped portions extending laterally to said covering means.

2. A fan comprising a hub, a plurality of blades extending from said hub, each of said blades having an outer portion of substantially constant pitch and curvature and an inner generally scooped portion, a disc covering only the inner scooped portions of said blades at the discharge side of the fan and of a radial extent to leave the outer blade portions of constant pitch and curvature open at the discharge side of the fan, and means securing said disc peripherally to the leading edges of the blades adjacent one side of the inner scooped portions of the blades, said inner scooped portions extending laterally to said disc.

3. A fan comprising a hub, a plurality of blades extending from said hub, each of said blades having an outer portion of substantially constant pitch and curvature and an inner generally scooped portion, a disc covering only the inner scooped portions of said blades at the discharge side of the fan and of a radial extent to leave the outer blade portions of constant pitch and curvature open at the discharge side of the fan, and means securing said disc peripherally to the leading edges of the blades adjacent one side of the inner scooped portions of the blades, the blades being undercut so that the disc lies flush with the leading edges of the blades, said inner of the scooped portions extending laterally to said disc.

4. A fan comprising a hub, a plurality of blades extending from said hub, each of said blades having an outer portion of substantially constant pitch extending from the tip of the blade to a point substantially midway between the tip of the blade and the axis of the fan, an inner blade portion of scooped formation inwardly of each of said outer blade portions, connecting portions 10 between the inner ends of said scooped blade portions and the hub, and a disc secured to the fan adjacent one side of the inner scooped portions of the blades and covering only the inner scooped and connecting portions of the blades and the hub at the discharge side of the fan and terminating peripherally at approximately the inner ends of the outer blade portions of substantially constant pitch, said inner scooped portions extending laterally to said covering means.

HERMAN C. HUEGLIN. 

